This application relates to electrical bus duct assemblies and more specifically relates to a novel joint for the connection of two separated bus ducts to one another in a manner which permits relative movement between the ends of the two bus ducts due to a seismic event or the like while maintaining electrical continuity between the ducts.
Bus duct is well known for electrical connection between generators and transformers, between transformers and switchgear assemblies, and to interconnect switchgear assemblies. This bus duct will frequently traverse buildings from floor to floor and from wall to wall on the same floor and therefore are subject to misalignment in any of three orthagonal directions due to a seismic event or other effects causing a relative shift in the duct support structure. Consequently, bus duct should normally contain a suitable joint along its length which permits a given amount of misalignment in the bus duct run.
In order to permit misalignement along the length of a bus run, it is known to provide an elongated corrugated rubber bellows enclosing the volume between the spaced ends of two bus duct units. These corrugated rubber bellows are expensive because of their size and contour and are commonly manufactured with a round cross-sectional shape. Because of the round cross-sectional shape, the bus duct enclosures must be rounded at their ends thus adding material costs and space requirements to the bus duct arrangement.